Acoustic device



Dec. 27, 1949 M. c. ROSENBLATT zmmm ACOUSTIC DEVICE Filed-Jan. 25, 1946IN V EN TOR.

. 97 Tommy Patented Dec. 27, 1949 UNITED STATES PATENT OFFICE 6 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) The invention described herein, if patented, may bemanufactured and used by or for the Government for governmentalpurposes, without the payment to meof any royalty thereon.

The invention relates to a plug for the external orifice of the earcanal.

It is an object of the invention to provide a soft rubber plug which isadjustably self-supporting in the ear.

It is a further object of the invention to provide a novel adjustingmeans for adapting the device to different sized ears.

It is a further object of theinvention to provide a flexible ear plughaving one end engaging the entrance to the ear canal and the other endengaging the ear crescent.

It is a further object of the invention to provide an adjustable supportcapable of general use, and able to resist a considerable amount ofcompressive force.

Whilethe ear canal is more or less opposite the ear crescentin the humanear, it enters the head at an angle of 25 or more to a line between theentrance to the canal and the anti-helix or crescent of the externalear. The flexibility of the stem of the ear plug comprising my inventioneffects a tight sealing of the entrance by the tip of the plug and afirm engagement of the crescent by the anchor because the stem can bebowed outwardly in an arc of 50 or 60 degrees between the canal entranceand the crescent.

The flexibility of the stem also increases its frictional resistance tothe sliding movement of the anchor when compressive forces are appliedat opposite ends of the device because the stem expands under suchpressure. This feature has utility in any field where a light adjustablesupport is needed.

Further objects of the invention will appear from a consideration of thefollowing description taken in connection with the accompanying drawing,in which:

Figure 1 is a vertical sectional view of a human ear takenlongitudinally of the ear canal showing the ear plug in place;

Figure 2 is a longitudinal sectional view of the ear plug showing theproper method of adjustment by a pulling action;

Figure 3 is a plan view of the plug showing its response to compressiveforce;

And Figure 4 is a plan view of the plug showing the surplus material ofthe stem being severed after a desired adjustment has been made; and

Figure 5 is a detailed sectional view of a modiflcation.

As shown in the drawing, the ear plug comprises a top or closure portionH] adapted to engage the entrance II to the ear canal, a cylindricalstem l2 of uniform diameter and a movable ear-engaging portion or anchorl3 slidably engaged on the stem. The central part I4 of the anchor has around bore [5 which fits snugly on the stem l2 when it is in unstressedcondition. Wings l6 extend oppositely from the central part [4 andconstitute means to engage the crescent of the ear. Their relation tothe central part I4 is such that when direct pressure is applied to thewings IS the bore l5 tends to close at the end nearer the tip, thusincreasing the friction between the stem and the anchor.

The entire device is made of soft rubber, either natural or synthetic,which permits it to assume the arcuate shape shown at I1 in Figure 1.This provides a light and comfortable pressure exerted at the correctangle both at the entrance to the ear canal and at the crescent oranti-helix at the anchor end. It also accomplishes the automatic lockingof the anchor l3 in the position required to fit the ear of the personusing the device.

As shown in Figures 2 and 3, the anchor l3 fits the stem I2 slidably andcan be moved along the stem easily in a direction away from the tip I!)if the tip is held in one hand and a pulling movement is applied to theanchor I3. However, if the tip I0 is held in one hand and the other handpushes wings I6 of the anchor toward the tip, the bore of the anchor hasa tendency to close at the end 3 and grip the stem l2, and the pressureagainst the tip ID, as transmitted through the stem, tends to expand thestem l2 as shown at H! in Figure 3, thereby increasing the resistance tothe motion of the anchor l3, and preventing movement of the anchor onthe stem. The resistance produced to compressive force is sufficient tocause a practically permanent adjustment of the anchor on the stem asfar as compressive force is concerned and thus an automatic andconvenient adjustment to a particular ear is provided. After theadjustment has once been made, any surplus portion of the stem l2 can becut off as shown at 20 in Figure 4, thus providing a plug which can becarried by the individual and slipped into the ear at any desired timewithout inconvenience or further adjustment.

It should be noted that the tip l0 does not go into the ear canal, itmerely closes it off at the entrance II. This seal is more effectivethan those obtained by devices which go into the ear canal itself. Suchdevices set up irritations and there is danger of infection and injurysince the ear canal becomes very tender directly beyond the entrance.

The plug is useful both as protection against sound in the case ofso1diers, workers in heavy industries, or light sleepers, or to preventthe entry of water into the ears. A lubricant, such as petroleum,gieil'y, may be used on the tip :or head of my device, although this isof no great importance unless it is used as a swimmers plug.

The adjustment of the plug should be made a little longer than thedistance between the entrance to the ear canal and the crescent toproduce the outward bowing of the stem I 2 shown at I! and enable thetip to engage the entrance to the ear canal at an inward angle or inalignment with the entrance. The device will also engage the crescentmore firmly in a slightly bowed condition, and therefore stay in the earbetter.

It will be obvious that the 'sli'dable connection between the anchor andstem is adapted to use a variety of adjustable supports where a moderateresistance to compression is required, such as would be furnished by arubber stem of sum-- e'i'ent softness and flexibility to respond to thecompressive force by bulging, and hence Jprevent sliding motion of theanchor.

Dne example of such use would be as a support orfitting Iorh'ea'ringaids, small head phones, etc. A form of my invention especially adaptedfor such uses is shown in Figure 5. 'In this embodi ment I2 representsthe stem, 6 the anchor, and 21 a passage extending through the tip andstem and o ening through the side of the stem at a point just ahead ofthe anchor when in its short est position. At this point a clip wouldhold such a thing as a head phone to the device, the device serving asan ear fitting.

The tip ll] of my device is somewhat larger than ear plugs as ordinarilyfound in the art. This over-size tip engages onl the entrance to thecanal, forming an e'fiective seal because the flexible, outwardly-bowedstein hold's'it at the pro er angle. This avoids both the liklihood ofirri= tating the canal and the necessity of making the device in aplurality of sizes, at least three sizes being necessary in the ordinaryplug.

While the effectiveness of the grip of the anchor on the stem isincreased by making both members of soft rubber, a satisfactoryconnection can be obtained with considerable variation in the degree ofhardness of one of the elements. In the ear plug the use of soft rubberthroughout contributes to the low cost and simplicity of the device,providing at the same time comfort at the points of engagement with theear, bowing of the stem to give both resilient pressure and correctangles of engagement with the tra'gus and antihelix and sufficientdeformation under pressure to lock the anchor on the stem. Though thecy-' lindrical stem is convenient and effective, the stem could be madein other configurations, as flat or square.

Having thus described my invention, what I claim is:

1. An ear-engaging device comprising a tip and a cylindrical stem ofuniform diameter, an anchor having a bore of substantially the samediameter mounted on the stem, said stem being laterally bendable underpressure and said anchor resisting movement airing the stem whencompressive force is applied to the anchor and one end of the stem, thedistance between the tip and the anchor being slightly greater than thedistance between the points to be engaged.

2. A sound-"transmitting device adapted to be worn in the ear andcomprising a tip, a stem, and a 'sli'dable anchor mounted on said stem,said anchor and said stem formed of a compressible material wherebypressure on the anchor and on one end of the stem expands the stem andprevents sliding motion of the anchor toward that end, said tip and stemhaving a sound transmitting passage.

3. An ear engaging "device comprising an elongated memberof resilientand compressible mate'- rial, one end of said member adapted to engagethe entrance to the ear canal and the other end to engage the crescentof the ear, said device being longer than the distance between thepoints to be engaged, whereby the elongated member assumes anoutwardly-bowed position when in place, ieifec tivel sealing theentrance to the canal and locking the device in place. v

4. An ear plug comprising an integral tip and stem of resilient andcompressible material, and an anchor member of similar material slidablelongitudinally of the stem.

5. An ear plug comprising an integral tip and stem of resilient andcompressible material, an anchor member of similar material slidablelongitudi'nally of the stem, and wings 'on the anchor member shaped tofit the crescent of the ear.

6. An ear plug com-prising an integral tip and stem of resilient andcompressible material, and an anchor member Of "similar materialsurround= ing said stern and islifla bly and s'n'u'gly engaging thesame.

MAURIGE C-. REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PATENTS Number Name Date 322,003 Plessner July 14, 1885750,625 Elliott Jan. 26, 1904 1,355,276 Schultz Oct. 12, "1920 FOREIGNPATENTS Number Country Date 456,207 Germany Aug. 4, 1928

